Audiphone



. June 24,-1930. A. w. HALL E'r A1.

AUDIPHONE Filed Sept. 14. 1928 Invenors JWM/weg.

Patented June 24, 1930 UNETED sjrnras ALFRED WINSLW HALL AND T01-IN E. DONNELLY, 0F PORTLAND, MAINE n AUDIPHONE ,Application led September 14, 1928. Serial No. 305,930.

Our inventionrelates to acoustic devices and applies more particularly to that type in which the power kof audition of the individual using the instrument is enlarged by .f1 the reproduction and ampliiication of the sound waves transmitted to his ear by diaphragmal vvibrations without resort to electrical means to augment the strength of theY reproduced sound.

Such a device, for instance, as our present invention which, we believe, is an improvement on the onepatented'by us on September 14th, 1926, numbered 1,599,961, is especially adaptable for use by persons aficted with impaired hearing, on account of its superior characteristics Ywith respect to acousticaly transmission, its portability, ease of application and simplicity in design and` construction.

'29 f A general object of ourinvention, considered in terms of structure, is to provide an audiphone with such an arrangement of dialphragms and connected parts as will not only reproduce articulation in amplified formbut in improved ytonal quality. p

AlspecificY object resides in the interpositionof an element, asV for example, a pin, betweenA two ldiaphragms, one preferably thicker' than the `other -and constructed of identical or different materials, the interposed element being either fixed in one diaphragm and in abutting contact with the other,'or suspended between the two so that, while' normally in contact with both, it mav upon extreme vibrations of either ofV theJ diaphragms becomeslightly separated from one or `the other'during the intervals between successive vibrations of the Ydialphrag'malY elements. y

40, `The thickerdiaphragm would, if free to actv alone, 'respond to thelower pitched tones and th'e'thi-nner to the higher ones,` but in co.-

Y action andvinterconnectnmthey collectively produce Va combination ofl controlled tones -f .45 such, for'instance, 4as does a bow when drawn simultaneously across the high and low pitch strings of astringed instrument. v I,To illustrate our invention we have prel pared the accompanying drawing which dis- .15.0 closes the'preferred embodiment thereof.

In this drawing,-

Fig. l is a sectional elevation of the audiphone, showing the diagraphm pin attached to one of the diaphragms;

Fig. 2 is a fragmentar' tion of the same, with t e between the two diaphragms;

Fig. 3 is a fragmentary sectional elevation of a modied form of the device; p

Fig. t is a detail view showing method 6e of attaching ythe pin to one of the diaphragms;

Fig. 5 is a face view of the pin-holding element used when the pin is suspended between the diaphragms; v A

Fig. 6 is a side elevation of the part shown in Fig. 5;

Fig. 7 is a sectional view on line 7#7, Fig. l; c,

F ig. 8 shows how the audiphone canbe 70 used in a head Set;y

Fig. 9 is a modified form of the device, incorporating a third diaphragm, and l Fig. l0 is a sectional view taken on line 10-10, Fig. 9. 75

Similar reference characters are employed to identify like parts in all views of the drawing. l

Referring to Fig. 1, 2O represents the u cylindrical body of the audiphone, an eXterior screw threaded portion 21 on which serves to receive and secure the cap 22 thereon. Y

Within the cap is an outer diaphragm 23 and inner diaphragm 24, the latter being relatively thinner. Interposed between the outer margins ofthe diaphragme is an annular ring 25 which serves as a spacer and abutting on thethinner of the two diat phragms is the flange portion of the frustoconical member 26. The four last mentioned elements are secured between the shoulder 27 of the cap 22 and theface ofthe body 20 by screwing the cap on to the body until all are firmly seated.

Although the audiphone is operable with diaphragms made of various materials, we prefer either yof two combinations,-first,- b'oth'of mica, and second,the outside diasectional elevapin suspended Y phragm of metal andthe inside of mica.

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for by hs 28, andin axial and radial ali vnt W 1lb* arl kl $9 in the member 26.

10 This member (26) is quite like a megaphone `rlilhvhtglif peft 11i ret Minner-the soundwaves passi through from the larger to thesmaller en The opnirlg in the smaller end aliiswith the hole 30 in the dished end of the 2U.

On the axis of the diap r 23 is-a -hole 31 in whieha pin' in seml bymeans of the clamp n 33. This pin may be attached to the 'pliragm in 'any one of varioua waysk but we prefer the nuts, one on for the'reaao? that ey serve admirab y to hld the pi :in any particular to which it is justed.

is' illustrated a construction' n F1 2 which, athough somewhat .more costly, appearai practlce to an improvynent on the metV od of allocating the pin m the dev i asshown in Fig, 1. An annular washer or co V34 claqged atits portions has an arm extending to and lfhyond its t0, arm the pin is secured, each end abutting on one 'f the e res 've diaph` The is era ly" sprung shghzl` y diaphragm when agembledn thesutlione so that a constantl vidi-it therewith 1S exerfd;

`pinxt si ncema befmadexnone V"mde adjustable, one part the Withthe cor n ine 26. The

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W39 p mf w40 the mi wiv n- ""pi, dhphmgmisfmm om @site ftowadmthe are tion and intensification of the sound waves close to the ear drum. This idea is shown in' Fi 3. Y Y iuch time, and energy have,` from time to time, been 'expended b numerous in 'entog'tT i in the conception an development of vices of a-.somewhatsi to thats-s '-J les thfjf; object sought has been attained with a cle; perception of the principles involved in the 5' ionphnie'ht; idthertmes the uestion as to just how the means employed ght about the successful result in experinientato has missinA lir in 'stndiiig f the function of the pin 32, its 've relatiomhip to the diaphragms aA the exaotpartit plays in the whole combination may, er any' not be in strict accord Awith advanced-scientific mason- 1 LV i n-Iowever, after diseloangthemthod we employ in this pix; inthe man, pmwulerls in www@ the diaphragm 24, we w11l recite what Wefbdiva to'be com sistent reasons ferrite mpllshig the marked improvementfwhichthas 4131111911) mlade m the quality. of Vour and poner, f ''.L' e Will repec, twhat have mmLthat www 7, are bonndhriidly. @t t gi and befo thmpinaj erp r we here Yat parallel, relat' up bmsht @mwN-mth i f1 by 13ml,fws'itantiwarq iai pronounced and rapid vibration and delivers to the listeners ear thereproduced sounds of V`higher register.

An important point to consider in connection with the vibratory action of the diaphragm 24 is the fact that a thin disc may be made to vibrate so rapidly that synchronism between the original and the reproduced sound waves is lost. In the present instance, the diaphragm 24 cannot reach this point of excessive vibratory action for the reason that it is held in check by the pin 32--the vibration being confined to one side of the plane in which the disc is secured. There seems, therefore, to be a coordination between the two diaphragms and the pin which tends to somewhat intensify the moderate tones and smooth down the harsh ones-acompromise, as it were, serving to increase the audibility of the reproduced sounds.

The modified form of the audiphone shown in Fig. 9 includes an additional diaphragm and in tests made of this type there apparently vwas an augmentation in the power of the reproduced sound waves, due doubtless to thefact that this style body is considerably longer and the taper of the conical member V26 more acute than corresponding elements in the type shown in Fig. 1. There is also a probability that the impingement of the sound waves through the member 26 directly on the central portion of the diaphragm 39 conduces to amore intense vibration of the latter than possibly would be the case was its whole area exposed to a less concentrated impact oflthese waves. The obj ect of the central hole 40 in the diaphragm 39 is so as not to choke the movement of the air within the body 26, this surmise being based on the fact that improved results obtained with the hole which were lacking without it.

We consider, however, that the arrangement shown in either Figs. 1, 2 or 3, to be a preferable embodiment of our invention, chiefly because. it is of simple construction, compact in form and effective in operation. And while we have disclosed in this application the function of the pin operable between two diaphragme as specially applicable to portable audiphones, we'desire to be understood that we do not restrict ourselves to its use for this particular. purpose, as obviously, other uses may be found wherein the principle involved in its present application can be utilized.

. Having described our invention, what we phragms in spaced relation, relatively, an annular cap securing said diaphragms and said annular ring to said body member, and n a pin disposed interjacent and axiallyl of said diaphragms and having each end unattached to and in normal contact with, but subject to intermittent separation from its adjacent diaphragm when vibrations of the latter occur.

2. An audiphone comprising in combination a cylindrical body having a dished end, an aperture in said dished end concentric with its axis, a frusto-conical member within said'body, the smaller end thereof extending through and for a spaced distance beyond the aperture in said dished end, perforations in the wall of said cylindrical body, perforations in said frusto-conical member aligning, respectively, with the perforations in said body, two diaphragme relatively spaced and of dissimilar thicknesses secured, at their outer margins only, to the full-open end of said body, and a pin suspended between said diaphragms with each end thereof normally contacting with its respective and adjacent diaphragm but subject to intermittent disengagement therefrom during vibrations of said diaphragm.

In testimony whereof we aiiix our signatures.

ALFRED WINSLOW HALL. JOHN R. DONNELLY.

` claim and desire to .secure by Letters Paty ent is l. An audiphone com rising in combination a hollow body mem er having perfora- Vtions inthe wall thereof, an inwardly-dished vend on said body having an aperture therethrough, a diaphragm, a second diaphragm, anV annular ring adapted to hold-saiddia- 

